Malaconothrus paraweigmanni Ermilov, 2016

Ermilov, Sergey G., 2016, A new species of the genus Malaconothrus (Acari, Oribatida, Malaconothridae) from Ecuador, Ecologica Montenegrina 9, pp. 31-37 : 32-37

Malaconothrus paraweigmanni Ermilov sp. nov.

( Figs 1–18 )

Diagnosis. Body size: 381–398 × 190–207. Body surface porose, covered by granular cerotegument, opisthosoma covered by reticulate cerotegument. Prodorsal setae setiform, long, barbed, interlamellar setae considerably longer than exobothridial setae ex 1. Lateral parts of prodorsum and notogaster with scale-like ledges. Notogastral ridges absent. Notogastral setae long, setiform, barbed; c 1, d 1, e 1 longer than other setae. Epimeral, genital and anal setae thin, smooth. Four pairs of genital setae present, anal setae well-developed. Adanal setae setiform, barbed, ad 1 longer than ad 2; ad 3 shortest. Legs tridactylous.

Description

Measurements. Body length: 398 (holotype, female), 381 (one paratype, female); notogaster width: 190 (holotype), 207 (one paratype).

Integument ( Figs 1 , 5–7 , 13, 14 ). Body color light grey. Body surface finely porose (clearly visible under high magnification) and covered by granular cerotegument (granules rounded or slightly elongated, their diameter or length up to 4). Opisthosoma with reticulate cerotegument.

Prodorsum ( Figs 1 , 6 ). Rostrum rounded. Lateral carinae well developed, reach to insertions of rostral setae, translamellar ridge absent between these setae. Each carina with medially-directed transverse extension (located laterally to lamellar setae). Rostral (ro, 36–41), lamellar (le, 49–53), interlamellar (in, 90– 94) and exobothridial (ex 1, 41–45) setae setiform, barbed, ro directed forwards. Exobothridial setae ex 2 represented by alveoli. Lateral parts of prodorsum (located laterally to ex 2) with scale-like ledges (Ld).

Notogaster ( Figs 1 , 5–7 , 15, 16 ). Anterior margin slightly convex medially. Lateral parts of notogaster with scale-like ledges. Posterior part with two slightly visible concavities. Notogastral ridges absent. Notogastral setae setiform, barbed; c 1, d 1, e 1 (90–94) longer than c 3, d 2, cp (73–77), c 2, e 2, f 2, h 1, h 2, h 3 (61–65) and p 1, p 2, p 3 (49–57). Lyrifissures well visible, ia located posteriorly to c 2, im – posteriorly to d 2, ip – laterally to h 1, ips and ih – on lateral parts of notogaster.

Gnathosoma ( Figs 2–4 , 17 ). Subcapitulum slightly longer than wide: 90–98 × 82–90. Subcapitular setae (h, 8; m, 16; a, 20) setiform, thin, smooth. Adoral setae (or 1, or 2, or 3, 4) minute, smooth. Palps (41–45) with setation 0–0–1–3–9(+ω). Setae cm setiform, longest on tarsi, other setae spiniform, from these, acm shortest and thinnest. Postpalpal setae (ep, 8–10) thin, erect, barbed. Solenidia (6) thickened, blunt-ended. Chelicerae (86–90) with two setae, cha (4–6) spiniform, smooth, chb (8) fusiform, barbed mediodistally. Trägårdh’s organs not visible.

Epimeral and lateral podosomal regions ( Figs 5, 6 ). Epimeral plates I separated medially, plates II and IV separated partially anteromedially, while plates III separated partially posteromedially. Epimeral setal formula: 3–1–3–3. Epimeral setae setiform, thin, smooth, 3a, 3b, 4c (20–24) longer than other setae (4–6).

Anogenital region ( Figs 5–7 ). Four pairs of genital setae (g 1 – g 4, 20) setiform, smooth, g 1 – g 3 directed backwards, g 4 – forwards. One pair of anal setae (an, 24) well developed, thin, smooth. Three pairs of adanal setae (ad 1, 61–65, ad 2, 49–53, ad 3, 36–41) setiform, barbed. Lyrifissures ian and iad distinct.

Legs ( Figs 6, 8 , 9–12 , 18 ). Tridactylous. Median claw thicker than laterals, all barbed dorsally. Formulae of leg setation and solenidia: I (1–5–3–4–11) [1–1–3], II (1–5–3–4–10) [1–1–1], III (2–3–2–2–10) [0–1–0], IV (0–2–2–2–10) [0–0–0]; homology of setae and solenidia indicated in Table 1 . Setae p, u, a, s, pv and ft” (on tarsi I, II) spiniform, ft’ (on tarsi I, II), ft (on tarsi III), ft” (on tarsi IV) thickened, tc thin, very long, famuli tubercle-like, inserted near ω 3, other setae setiform. All solenidia simple, blunt-ended.

Material examined. Holotype (female) and one paratype (female): Ecuador, 0°25'8.04''S, 79°0'14.04''W, Reserva de Bosque Integral Otonga , near San Francisco de las Pampas, 2000–2200 m a.s.l., sifted litter from forest, 7.XI.1996 (G. Onore).

Type deposition. The holotype is deposited in the collection of the Senckenberg Institute , Görlitz, Germany; one paratype is deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia.

Etymology. The specific name paraweigmanni refers to the similarity between the new species and Malaconothrus weigmanni Colloff, 2013 .

Remarks. The new species is most similar to Malaconothrus weigmanni Colloff, 2013 from Papua New Guinea in the main morphological traits (notogaster with reticulate cerotegument; notogastral ridges absent; majority of notogastral setae long; interlamellar setae considerably longer than exobothridial setae ex 1; adanal setae ad 1 longer than ad 2, ad 3 shortest; tridactylous legs). However, the present new species differs from M. weigmanni by the smaller body size (381–398 × 190–207 vs. 444–450 × 246–253), notogastral setae barbed (vs. smooth) and comparatively long anal setae (vs. minute).

Figures

Figures 1–4. Malaconothrus paraweigmanni sp. nov.: 1 — dorsal view; 2 — subcapitulum, ventral view; 3 — palp, right, antiaxial view; 4 — chelicera, left, paraxial view. Scale bar 50 μm (1), 20 μm (2, 4), 10 μm (3).

Figures 5–8. Malaconothrus paraweigmanni sp. nov.: 5 — ventral view (gnathosoma and legs except trochanters not shown); 6 — lateral view (gnathosoma and legs except basal parts not shown); 7 — posterior view; 8 — famulus, solenidia and setae ft on leg tarsus I. Scale bar 50 μm (5–7), 10 μm (8).

Figures 9–12. Malaconothrus paraweigmanni sp. nov.: 9 — tibia and tarsus of leg I, right, antiaxial view; 10 — tibia and tarsus of leg II, right, antiaxial view; 11 — genu, tibia and tarsus of leg III, left, antiaxial view; 12 — genu, tibia and tarsus of leg IV, left, antiaxial view. Scale bar 20 μm.

Figures 13–18. Malaconothrus paraweigmanni sp. nov., microscope images: 13 — granulate cerotegument in median part of prodorsum; 14 — reticulate cerotegument in median part of notogaster; 15 — notogastral lateral ledge; 16 — basal part of notogastral seta d2; 17 — palp and part of subcapitulum; 18 — claws of tarsi III and IV. Scale bar 10 μm (13, 16), 20 μm (14, 15, 17, 18).